Cable transportation system and relative operating method

ABSTRACT

A cable transportation system has a pull cable; at least one transportation unit moving along a given path and connectable selectively to the pull cable by a coupling device; at least one passenger station where the transportation unit is detached from the pull cable; and an auxiliary drive device having a linear electric motor extending along a portion of the given path to move the transportation unit along the passenger station.

PRIORITY CLAIM

This application is a national stage application of PCT/EP2008/060247, filed Aug. 4, 2008, which claims the benefit of and priority to Italian Patent Application No. MI2007A 001618, filed on Aug. 3, 2007, the entire contents of which are incorporated herein.

TECHNICAL FIELD

The present disclosure relates to a cable transportation system.

More specifically, one embodiment of the present disclosure relates to a cable transportation system comprising a pull cable; at least one transportation unit moving along a given or designated path and connectable selectively to the pull cable by a coupling device; at least one passenger station where the transportation unit is detached from the pull cable; and an auxiliary drive device extending along the passenger station to move the transportation unit along a portion of the given or designated path.

BACKGROUND

Certain known cable transportation systems include systems in which the transportation units are suspended from a pull cable, such as chair-lifts or cable-cars, as well as urban transportation systems of the type described in EP Patent Number 0 687 607 B1 and EP Patent Number 1 088 729 B1, in which the transportation units rest on rails and are drawn by a pull cable.

In both of these known cable transportation systems, the auxiliary drive device comprises a succession of wheels aligned along the passenger station. The wheels are rotated by a mechanism operated by the pull cable or, in alternative embodiments, by an actuator independent of the cable, and engage the transportation unit to move it along a given path portion in accordance with a given optimum speed profile comprising a deceleration stage and an acceleration stage.

The wheels of the auxiliary drive device are connected to one another by a drive belt looped about two pulleys. Each wheel is integral with a respective pulley and, by appropriately selecting the pulley diameters, the speed of the adjacent wheel can be increased or reduced to accelerate or decelerate the transportation unit.

Since the auxiliary drive device may comprise curved portions—as in the case of auxiliary drive devices at turnaround stations of cable transportation systems such as chair lifts or cable-cars—power is transmitted between adjacent wheels of the auxiliary drive device using bevel gears: each wheel is integral with a bevel gear meshing with a bevel gear interposed between the two adjacent wheels.

Though effective, currently used auxiliary drive devices are extremely complicated to produce, on account of the high degree of precision involved in assembling the belt, pulley, and bevel gear connections. Moreover, currently used auxiliary drive devices are not very flexible, and fail to provide for easy, relatively low-cost variations in speed.

SUMMARY

It is an object of the present disclosure to provide a cable transportation system designed to eliminate the drawbacks of such known art.

According to one embodiment of the present disclosure, there is provided a cable transportation system, characterized in that the auxiliary drive device comprises a linear electric motor extending along a path portion.

The present disclosure also relates to a method of operating a cable transportation system.

According to one embodiment of the present disclosure, there is provided a method of operating a cable transportation system comprising a pull cable; at least one transportation unit moving along a given or designated path and connectable selectively to the pull cable by a coupling device; and at least one passenger station where the transportation unit is detached from the pull cable; the method being characterized by comprising the step of moving the transportation unit along the passenger station by means of a linear electric motor extending along the path portion.

Additional features and advantages are described in, and will be apparent from, the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE DRAWINGS

A number of non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying drawings, in which:

FIG. 1 shows a partly sectioned plan view, with parts removed for clarity, of a cable transportation system in accordance with one embodiment of the present disclosure;

FIG. 2 shows a larger-scale, partly sectioned front view, with parts removed for clarity, of a detail of the FIG. 1 cable transportation system;

FIG. 3 shows a larger-scale view in perspective, with parts removed for clarity, of a detail of the FIG. 1 cable transportation system;

FIG. 4 shows a plan view, with parts removed for clarity, of a cable transportation system in accordance with another embodiment of the present disclosure;

FIG. 5 shows a larger-scale, partly sectioned front view, with parts removed for clarity, of a detail of the FIG. 4 cable transportation system;

FIG. 6 shows a partly sectioned side view, with parts removed for clarity, of a detail of the FIG. 4 cable transportation system;

FIG. 7 shows a partly sectioned plan view, with parts removed for clarity, of a detail of the FIG. 4 cable transportation system;

FIGS. 8, 9 and 10 show larger-scale plan views, with parts removed for clarity, of a detail in FIG. 7;

FIG. 11 shows a view in perspective, with parts removed for clarity, of a variation of the present disclosure; and

FIG. 12 shows a view in perspective, with parts removed for clarity, of a further variation of the present disclosure.

DETAILED DESCRIPTION

Referring now to the example embodiments of the present disclosure illustrated in FIGS. 1 to 12, number 1 in FIG. 1 indicates a passenger cable transportation system. In the FIG. 1 example embodiment, cable transportation system 1 comprises an endless pull cable 2; and a number of transportation units 3, of the type suspended from pull cable 2 (such as chair-lift chairs or cable-cars) which are moved along a given or designated path P1.

Cable transportation system 1 comprises a passenger station 4 (e.g., a turnaround station) which comprises a pulley 5 rotating about a substantially vertical axis A, and about which pull cable 2 is wound partly; a control unit 6; and a frame 7 supporting transportation units 3 at passenger station 4.

Frame 7 extends along a portion of path P1, and comprises a U-shaped beam 8 supporting a number of supporting structures 9.

With reference to FIG. 2, beam 8 supports a U-shaped linear stator 10 (FIG. 1); and each supporting structure 9 supports three guides 11, 12, 13. Each transportation unit 3 comprises a suspension arm 14; and a trolley 15 which engages guides 11, 12, 13 at station 4, as shown in FIG. 2.

Trolley 15 comprises a coupling device 16 for selectively connecting trolley 15 and transportation unit 3 to the pull cable 2, and which in FIG. 2 is shown releasing pull cable 2.

Trolley 15 has three rollers 17, 18, 19, each of which engages a respective guide 11, 12, 13 to define a given position of trolley 15. For which purpose, guide 11 has a C-shaped cross section, and is engaged by respective roller 17.

Each transportation unit 3 also comprises a slide 20 integral with trolley 15, and which cooperates with stator 10 to move transportation unit 3 through station 4.

Slide 20 is connected to trolley 15 and arm 14 by a flange 21.

Stator 10 and slide 20 define a synchronous linear electric motor 22 operating at passenger station 4. Each transportation unit 3 moving through passenger station 4 is powered by linear motor 22 which is defined by respective slide 20 and by stator 10, and defines an auxiliary drive device of cable transportation system 1.

With reference to FIG. 3, stator 10 comprises an elongated body 23 of nonferrous material (for example a glass-fibre-reinforced epoxy resin); a succession of coils 24 embedded in the nonferrous material; and two flanges 25 to fix elongated body 23 to beam 8. Elongated body 23 has a rectangular cross section, and two opposite, parallel, substantially horizontal main faces 26. Each coil 24 is defined by a plate 27 which is perpendicular to faces 26, is wound to form two windings 28, and has two free ends 29 supplied with electric current.

Construction wise, in one embodiment, stator 10 is defined by modular units (UM) (FIG. 3), each comprising three successive coils 24. In this embodiment, elongated body 23 is formed by arranging modular units (UM) one after the other.

Each slide 20 comprises a plate 30 bent into a U and having two opposite parallel faces 31, along which are arranged two sets 32 of permanent magnets 33.

The two sets 32 of permanent magnets 33 face each other at such a distance apart as to fit slide 20 about stator 10. That is, each set 32 of magnets 33 is substantially parallel to and faces a face 26 of elongated body 23 to form a gap between permanent magnets 33 and respective face 26.

Each coil 24 is supplied independently of the other coils 24 with electric current, the intensity (I) and frequency (F) of which are modulated by a respective modulator (M) connected to control unit 6 (FIG. 1). In one embodiment, coils 24 are divided into groups, in which each group is supplied with the same current frequency and intensity.

With reference to FIG. 1, depending on a number of position signals (PS) and speed signals (V) related to the positions and speeds of transportation unit 3, and as a function of an optimum speed profile (VR), control unit 6 transmits a regulating signal (VT) to modulator (M), which accordingly regulates the supply current intensity and frequency of the groups of electric coils 24 to produce a speed of transportation unit 3 as close as possible to the optimum speed profile (VR).

For this purpose, cable transportation system 1 comprises a succession of sensors 34 located along the given or designated portion of path P1 at station 4, and which, in the example shown, are proximity sensors for detecting transit of transportation units 3 along station 4 at a given instant. Control unit 6 acquires position signals (PS) from sensors 34, calculates speed signals (V), and compares speed signals (V) with the optimum speed profile (VR).

The optimum speed profile (VR) comprises a deceleration stage; a constant, relatively low-speed travel stage to allow passengers to alight and board transportation unit 3; and an acceleration stage to accelerate transportation unit 3 to a speed as close as possible to the speed of pull cable 2, before connecting transportation unit 3 to the pull cable 2.

Dividing coils 24 into groups comprises forming a group of coils 24 defining a deceleration portion; a group of coils 24 defining an acceleration portion; and a group of coils 24 defining a constant-speed portion between the deceleration and acceleration portions.

The acceleration portion and deceleration portion may comprise a number of groups of coils 24 supplied independently of one another, and in which each group provides for moving a respective transportation unit 3.

Linear motor 22 also provides for other operating modes, such as an emergency operating mode in which all the transportation units 3 at station 4 are stopped automatically, and which short-circuits all the electric coils 24.

Another characteristic of linear motor 22 is that of also reversing transportation units 3 at station 4. This operating mode is achieved by inverting the stage sequence, and is useful in equally spacing transportation units 3.

Number 35 in the FIG. 4 embodiment indicates an urban cable transportation system comprising two parallel rails 36 defining a path P2; a continuous pull cable 37 extending along path P2; a transportation unit 38 moving along path P2 and connectable selectively to the pull cable 37; a passenger station 39 extending along a portion of path P2, at which each transportation unit 38 is slowed down, stopped to enable passengers to alight and board transportation unit 38, and accelerated; and a control unit 40.

With reference to FIG. 5, at the portion of path P2 at passenger station 39 (FIG. 4), cable transportation system 35 comprises pulleys 41 supporting pull cable 37; and a stator 42 structurally identical to stator 10 and therefore described using the same reference numbers. Unlike stator 10, linear stator 42 is positioned with faces 26 substantially vertical.

With reference to FIG. 7, each transportation unit 38 comprises a frame 43; and four wheels 44 connected in pairs along respective axes and resting on top faces of rails 36, as shown more clearly in FIG. 5. With reference to FIG. 5, frame 43 supports pairs of guide wheels 45 resting on inner faces of rails 36. In the example shown, each wheel 44 is associated with a pair of guide wheels 45.

Frame 43 supports a coupling device 46 for connecting transportation unit 38 selectively to the pull cable 37; a cab 47 on top of frame 43; and a group of slides 48 located beneath frame 43 and which engage linear stator 42. In the FIG. 6 example, transportation unit 38 has three slides 48 arranged in series. Each slide 48 has the same technical characteristics described with reference to slide 20, and comprises a trolley 49 which engages two parallel opposite guides 50 (FIG. 5) to equally space slide 48 with respect to linear stator 42 in a direction substantially perpendicular to the lengthwise extension of rails 36 (FIG. 5).

Trolley 49 comprises four rollers 51 fixed to slide 48, as shown more clearly in FIGS. 8, 9 and 10. Slide 48 is connected to frame 43 by two parallel arms 52 hinged to frame 43 and slide 48 about vertical axes to form, with frame 43 and slide 48, an articulated quadrilateral. At least one of arms 52 is preferably connected to a spring (not shown) to position slide 48 in such a manner as to engage guides 50, which are flared at the ends.

Linear stator 42 and slides 48 define a linear motor 53 forming an integral part of an auxiliary drive device for moving transportation units 38 through passenger station 39.

With reference to FIG. 4, cable transportation system 35 comprises sensors 54—in the example shown, proximity sensors—arranged along the portion of path P2 extending along passenger station 39 to acquire a number of position signals (PS) related to the instantaneous position of transportation unit 38 and by which to calculate speed signals (V) related to the speed of transportation unit 38. Position signals (PS) and speed signals (V) are compared with an optimum speed profile (VR) in control unit 40, which transmits a regulating signal (VT) to modulator (M), which accordingly regulates electric current intensity and frequency, and powers groups of electric coils 24 to produce a speed of transportation units 38 as close as possible to optimum speed profile (VR).

In other words, operation is similar to that described with reference to the first embodiment of the present disclosure, except for the stop at passenger station 39.

In this case, optimum speed profile (VR) only comprises a deceleration stage and an acceleration stage, separated by a stop stage of unpredictable duration.

In the embodiments described, linear stators 10 and 42 comprise coils 24, and slides 20 and 48 comprise magnets 33.

With reference to FIG. 11, the linear stator 55 comprises permanent magnets 33, and the slide 56 comprises coils 24. The component parts in FIG. 11 are indicated using the same reference numbers as in FIG. 3. Coils 24 associated with slide 56 are powered by a strip (not shown), which runs along the path through passenger station 4, 39, and by sliding contacts along the strip, whereas stator 55 is fixed to station 4, 39.

The embodiments described so far refer specifically to a synchronous linear motor. FIG. 12 shows a variation comprising an asynchronous linear electric motor 58 for application to cable transportation systems 1 and 35.

In the FIG. 12 example, asynchronous linear electric motor 58 comprises a stator 59 and a slide 60. Stator 59 is defined by a metal blade 61, and slide 60 comprises a plate 62 bent into a U and housing electric coils 63 facing blade 61.

In a variation not shown, the slide comprises a metal blade, and the stator comprises a plate bent into a U and housing electric coils.

The FIG. 1 transportation system 1 comprises only one cable, namely a pull cable, it being understood, however, that the present disclosure also applies to cable transportation systems comprising a number of cables, such as a pull cable and one or more supporting cables.

It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims. 

1) A cable transportation system (1; 35) comprising a pull cable (2; 37); at least one transportation unit (3; 38) moving along a given path (P1; P2) and connectable selectively to the pull cable (2; 37) by a coupling device (16; 46); at least one passenger station (4; 39) where the transportation unit (3; 38) is detached from the pull cable (2; 37); and an auxiliary drive device extending along the passenger station (4; 39) to move the transportation unit (3; 38) along a portion of said given path (P1; P2); the cable transportation system (1; 35) being characterized in that the auxiliary drive device comprises a linear electric motor (22; 53; 57; 58) extending along said portion of said given path (P1; P2). 2) A system as claimed in claim 1, characterized in that the linear electric motor (22; 53; 57; 58) comprises a linear stator (10; 42; 55; 59) extending along said portion of said given path (P1; P2); and a slide (20; 48; 56; 60) associated with said transportation unit (3; 38). 3) A system as claimed in claim 2, characterized in that the slide (20; 48; 56; 60) and the linear stator (10; 42; 55; 59) are connected magnetically to each other along said portion of said given path (P1; P2). 4) A system as claimed in claim 2 or 3, characterized in that the linear electric motor is a synchronous linear electric motor (22; 53; 57). 5) A system as claimed in claim 4, characterized in that the linear stator (10; 42; 55) comprises a succession of electric coils (24) or permanent magnets (33); the slide (20; 48; 56) comprising a group of permanent magnets (33) or electric coils (24). 6) A system as claimed in claim 5, characterized in that each slide (20; 48) comprises two sets (32) of permanent magnets (33); each set (32) of permanent magnets (33) facing the other set (32) of permanent magnets (33), and both sets (32) of permanent magnets (33) facing the linear stator (10; 42) along said passenger station (4). 7) A system as claimed in claim 5 or 6, characterized in that the linear stator (10; 42) comprises a succession of electric coils (24) powered selectively with electric energy. 8) A system as claimed in claim 7, characterized in that each electric coil (24) is powered independently of the other electric coils (24). 9) A system as claimed in claim 7, characterized in that the electric coils (24) are divided into groups, each group of adjacent electric coils (24) being powered independently of the other groups. 10) A system as claimed in any one of claims 7 to 9, characterized in that the linear stator (10; 42) comprises an elongated body (23) of nonferrous material in which the electric coils (24) are embedded. 11) A system as claimed in claim 10, characterized in that the elongated body (23) has two opposite parallel faces (26), each facing the'slide (20; 48). 12) A system as claimed in claim 10 or 11, characterized in that the elongated body (23) is defined by a succession of adjacent modular units (UM). 13) A system as claimed in claim 5, characterized in that each slide (56) comprises a succession of electric coils (24). 14) A system as claimed in claim 13, characterized in that the linear stator (55) comprises two sets (32) of permanent magnets (33); each set (32) of permanent magnets (33) facing the other set (32) of permanent magnets (33), and both sets (32) of permanent magnets (33) facing the electric coils (24) of the slide (56). 15) A system as claimed in any one of claims 1 to 3, characterized in that the linear electric motor is an asynchronous linear electric motor (58) comprising a slide (60) comprising electric coils (63); and a stator (59) comprising a metal blade. 16) A system as claimed in any one of claims 1 to 3, characterized in that the linear electric motor is an asynchronous linear electric motor comprising a slide comprising a metal blade; and a stator comprising electric coils. 17) A system as claimed in one of claims 7 to 16, characterized by comprising a control unit (6; 40), and a number of electric current intensity and electric current frequency modulators (M) for powering respective electric coils (24; 63); said control unit (6; 40) supplying a number of regulating signals (VT) to each of the modulators (M), which regulate the current intensity and current frequency to be supplied to the respective coils (24; 63) as a function of the regulating signal. 18) A system as claimed in claim 17, characterized by comprising a number of sensors (34; 54) arranged successively along said portion of said given path (P1; P2) along said passenger station (4; 39), and each for emitting a position signal (PS) related to the position of each transportation unit (3; 38). 19) A system as claimed in any one of claims 4 to 18, characterized in that guides (11, 12, 13; 50) are located parallel to the linear stator (10; 42) along the passenger station (4; 39); the transportation unit (3; 38) comprising a trolley (15; 49) which selectively engages said guides (11, 12, 13; 50) to keep the slide (20; 48) at a given distance from the linear stator (10; 42). 20) A system as claimed in claim 19, characterized in that the trolley (49) is movable with respect to the transportation unit (38). 21) A system as claimed in claim 20, characterized in that the trolley (49) is fixed rigidly to the slide (48) and hinged to said transportation unit (38). 22) A system as claimed in claim 20 or 21, characterized in that said cable transportation system (35) comprises two rails (36) extending along said given path (P2); the transportation unit (38) comprising wheels (44) resting on said rails (36). 23) A system as claimed in claim 19, characterized in that said transportation unit (3) is of the type suspended from the pull cable (2) by said coupling device (16). 24) A system as claimed in any one of claims 4 to 23, characterized by comprising a number of transportation units (3; 38); each transportation unit (3; 38) being associated with at least one slide (20; 48; 56; 60). 25) A method of operating a cable transportation system (1; 35) comprising a pull cable (2; 37); at least one transportation unit (3; 38) moving along a given path (P1; P2) and connectable selectively to the pull cable (2; 37) by a coupling device (16; 46); and at least one passenger station (4; 39) where the transportation unit (3; 38) is detached from the pull cable (2; 37); the method being characterized by comprising the step of moving the transportation unit (3; 38) along the passenger station (4; 39) by means of a linear electric motor (22; 53; 57; 58) extending along a portion of said given path (P1; P2). 26) A method as claimed in claim 25, characterized in that the linear electric motor (22; 53; 57; 58) comprises a linear stator (10; 42; 55; 59) extending along said portion of said given path (P1; P2); and a slide (20; 48; 56; 60) associated with said transportation unit (3; 38); the method providing for connecting the slide (20; 48; 56; 60) and the linear stator (10; 42; 55; 59) magnetically along said portion of said given path (P1; P2). 27) A method as claimed in claim 26, characterized in that each slide (20; 48; 56; 60) comprises permanent magnets (33). 28) A method as claimed in claim 27, characterized in that the linear electric motor (22; 53; 57; 58) comprises electric coils (24) powered selectively with electric energy; the method providing for powering each electric coil (24; 63) independently of the other electric coils (24; 63). 29) A method as claimed in claim 28, characterized by modulating the intensity of the current supply to each electric coil (24; 63). 30) A method as claimed in claim 29, characterized by modulating the frequency of the electric current supply to each electric coil (24; 63). 31) A method as claimed in claims 29 and 30, characterized by comprising the steps of acquiring a number of position signals (PS) related to the position of the transportation unit (3; 38), and a number of speed signals (V) related to the speed of the transportation unit (3; 38); and supplying a regulating signal (VT) as a function of a comparison between the position (PS) and speed (V) signals and an optimum speed profile (VR) along the passenger station (4; 39). 32) A method as claimed in any one of claims 26 to 31, characterized by comprising the step of guiding the transportation unit (3; 38) along the passenger station (4; 39) by means of guides parallel to the linear stator (10; 42; 55; 59); the transportation unit (3; 38) comprising a trolley (15; 49) which selectively engages said guides (11, 12, 13; 50) to keep the slide (20; 48; 56; 60) at a given distance from the linear stator (10; 42; 55; 59). 